1. Field of the Invention
The present invention relates to an image display system including a transmitter device that can transmit video data and audio data and a receiver device that is connected via an HDMI cable to the transmitter device and that has the capabilities of displaying video based on video data from the transmitter device and of outputting audio based on audio data from the transmitter device. The present invention also relates to a receiver device for use in such an image display system.
2. Description of Related Art
Thanks to advancements in liquid crystal panel fabrication technologies, recent years have seen remarkable developments in the super-high definition displays of television monitors that are designed to be used in combination with DVD players or the like. This has made it possible to display a huge amount of video data with high definition. In such a television monitor, to cope with a huge amount of video data and audio data transmitted from a DVD player or the like, an interface called HDMI (high-definition multimedia interface) is used.
The HDMI is an interface designed for the transfer of video data and audio data from a transmitter device, such as a DVD player, to a receiver device, such as a television monitor or a projector. The HDMI is an expanded version of the conventionally formulated DVI (digital visual interface for computer) Ver. 1.0. Specifically, whereas the DVI is formulated to handle the transmission of video data alone, the HDMI is formulated to handle the transmission, via a single cable, of not only video data but also audio and other data. Furthermore, the HDMI permits the transfer of high-quality, multichannel audio data along with high-definition, multiple-format video data.
The HDMI can also be used in DDC (display data channel) communication to transfer various kinds of data (for example, information on a monitor, such as an EDID data structure). EDID (extended display identification data) includes, to name a few, the resolutions at which a receiver device can receive data, information on audio streams, and information on the speakers available on the part of the receiver. Moreover, the HDMI permits the transfer of video data and audio data via a single cable, and thus has the advantage of eliminating the trouble of connecting a number of cables. For example, in a case where contents of a CSS (content scrambling system) is outputted from a DVD player, the HDMI is an interface approved by the CPAC (copy protection advisory council).
The above-mentioned DDC refers to a type of communication, and denotes a network over which data relating to display conditions for video data and conditions for audio data is, along with other data relating to an HDMI monitor, transmitted to a DVD player. The DDC is connected to a communication line within the DVD player, and is used to establish a network between the DVD player and the HDMI monitor. The above-mentioned CSS denotes a system that encrypts data for recording and decrypts it for playback.
In a conventionally known image display system (for example, see JP-A-2005-109703), the HDMI described above is used to connect together a DVD player as a transmitter device and an HDMI monitor as a receiver device. According to this conventional technology, the DVD playback device (DVD player) acquires, from the HDMI monitor beforehand, condition information representing the display conditions of the HDMI monitor and, based on the acquired condition information, converts image information (video data), makes settings related to the image information on a display device, and outputs the converted image information to the HDMI monitor.
However, according to the conventional technology disclosed in JP-A-2005-109703, although the DVD playback device, based on the acquired condition information, converts image information, makes settings related to the image information on a display device, and outputs the converted image information to the HDMI monitor, when the EDID information that the DVD playback device has received from the HDMI monitor is irrelevant, since the HDMI monitor does not so operate as to make the DVD playback device acquire correct EDID information, inconveniently, the image information from the DVD playback device cannot be displayed on the HDMI monitor.
That is, according to the conventional technology, when the EDID information that the transmitter device that outputs video data and audio data has received from the receiver device is irrelevant, the receiver device can transmit EDID information in response to a request from the transmitter device, but cannot confirm whether or not its acquisition has correctly been performed, and, if not, inconveniently, the image information from the transmitter device cannot be displayed on the receiver device.
According to the conventional technology disclosed in JP-A-2005-84881, an image processing device receives parameter information and, based on the received parameter information, performs image processing, and request an image display device to change parameter information. When the EDID information that the image processing device has receives is irrelevant, the image display device cannot confirm whether or not the EDID information is irrelevant. Thus, this technology does not solve the aforementioned inconveniences.
According to the conventional technology disclosed in JP-A-2000-194346, as the display state changes according to user control or the like, EDID information is updated, and the updated EDID information is transmitted to a personal computer. When the EDID information that the personal computer has received from a display device is irrelevant, the display device cannot confirm whether or not the personal computer has correctly received it, and, if not, inconveniently, the image information from the personal computer cannot be displayed on the display device.